Dual mode receiving and transmitting antenna



July 1, 1969 RONEY ET AL 3,453,621

DUAL MODE RECEIVING AND TRANSMITTING ANTENNA Filed July 8, 1966 Sheet 0f 3 Robert K. Roney, Harold A. Rosen, Thomas Hudspeth, Herbert T. Suyemmsu, Meredith K. Eick,

INVENTORS.

ATTORNEY.

' @ECE/VEB R. K. RONEY 3,453,621

DUAL MODE RECEIVING AND TRANSMITTING ANTENNA July 1, 1969' ET AL Sheet 2) of3 Filed July 8, 1966 United States Patent O U.S. Cl. 343-100 16 Claims ABSTRACT OF THE DISCLOSURE A system that collects linearly polarized energy and couples it either equally to two receivers, or by a selection device, couples all of the energy to one receiver. Upon failure of the selection device, the energy is always equally coupled to the two receivers. A property of the selection device is also utilized to provide a signal related to the spin angular phase of a spinning body on which the antenna is mounted. The system, which is operable for both reception and transmission, provides a high antenna gain with a relatively wide bandwidth and with low loss in the feed system.

This invention relates to antenna apparatus, and more particularly to a novel antenna and coupling system for transmitting and receiving purposes.

The invention is particularly applicable to directive signalling systems in which a pair of receivers are used for redundancy purposes. In such a system, it may be desired to alternately switch the receivers into operation; to operate both receivers simultaneously; or to operate one receiver and use the other as a standby receiver.

A disadvantage of previously known antenna arrangements for receivers to be used for redundancy relates to undesired loading of feed circuits. If two receivers operating at the same frequency are placed in parallel, for example, avoidance of loading the feed circuits of both would heretofore require either the use of separate antennas for the receivers, or a single antenna together with a switching device for disconnecting one of the receivers. Such alternatives are undesirable because of complexity, unreliability, loss of receiver power, and loss of control in the event of failure of switching devices.

It is also desired to transmit and receive signals over a wide frequency band, e.g., 500 mHz. (megahertz) or more, but with physically small antenna structures. Also, bandwidths of such magnitudes preferably are attained with relatively high gain antennas, and losses must be small to retain good signal-to-noise ratio over the band. Suflicient gain can be achieved with arrays of presently known antennas. However, such arrays tend to become sharply tuned, thereby narrowing the useable bandpass to a substantially smaller magnitude than is desired.

It is an object of this invention to provide an antenna system operable over a wide frequency band without the disadvantages of prior art antenna arrangements.

It is another object of this invention to provide simple apparatus for coupling received energy equally to two receivers.

A further object of this invention is to provide an improved antenna and coupling system serving a pair of receivers, and which is capable of coupling all of the received energy to one or the other of the receivers.

It is also an object of our invention to provide improved antenna apparatus for use in receiving or transmitting signals.

Another object of this invention is to provide an improved repeater system and associated antenna structures.

ICC

The above and other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings of illustrative embodiments thereof, in which:

FIGURE 1 is a side elevation view, partly broken away, of a receiving antenna and waveguide coupler in accordance with the invention for dividing received power between two receivers;

FIGURE 2 is a sectional view taken along the lines 2-2 of FIGURE 1;

FIGURE 3 is a perspective view, partly broken away, of a receiving antenna and associated waveguide containing polarization controls for causing all of the received power to be applied to one of two receivers;

FIGURE 4 illustrates a repeater system of our invention showing antenna and waveguide coupling means in side elevation and a block diagram of means for extracting phase information from received energy and for selectively coupling all of the received energy to one or the other of a pair of receivers, and for transmitting signals in response to operation of the receivers;

FIGURE 5 illustrates an antenna structure as in FIG- URE 3 and means for effecting transmission of signals thereby; and

FIGURE 6 illustrates a pair of the antenna structures of FIGURE 1 for reception and transmission, and a block diagram of simplified means for effecting transmission of signals derived from the received signals.

Referring to FIGURES 1 and 2, there is shown an antenna structure 10 which is carried by a supporting structure or body, indicated generally in phantom lines at 12. The antenna structure 10 is formed of a cylindrical waveguide 14 which at its upper end is provided with a plurality of spaced slots 16. As shown, the slotted portion of the waveguide is located between flared frustoconical reflectors 18, 20. Within the waveguide, and disposed below the slots 16, in polarization converter means, here shown in the form of diametrically opposed quarter-wave plates 22, 24. Below the plates 22, 24 are a pair of output probes 26, 28, carried by respective connectors 30, 32 which are supported in the waveguide wall, and which are connected to respective receivers 34, 36.

As will become apparent, the reflectors 18, 20 are not essential to the invention. Such reflectors may be eliminated to provide a much wider power pattern in the vertical direction. Further, a narrow pattern in the vertical direction may be obtained without the reflectors. Another suitable arrangement is the provision of two or more sets of slots as shown which are vertically spaced from the upper end of the waveguide, and suitably spaced and dimensioned, in conformance with conventional design criteria, to provide a power pattern narrowed as desired.

With this arrangement, energy incident upon the antenna is coupled to the waveguide 14 in a TE mode. However, the quarter-wave plates 22, 24 cause the linearly polarized wave to be converted so that the energy is divided equally between the receivers 34, 36. Energy is received by the antenna 10 at any angle of rotation of the structure 12 and the linearly polarized wave is bent into the waveguide 14 to propagate down as a TE (linearly polarized) wave. The plates 22, 24 which rotate with the axis converts the TE wave to a time varying polarized wave that couples equal energy to each probe 26 and 28, which probes have a 45 degree relationship with the plates. The time varying polarized wave at the lower end of the quarter wave plates varies from linear to circular as the structure rotates and the orientation of the plates with regard to the two probes is such that at all times during a revolution of the waveguide 14, an equal amount of the incident energy is coupled to each of the probes. Each one-quarter revolution of the waveguide provides a linear polarized wave at the probes, which occurs when the E vector is in the plane of or at right angles to the plates. The polarization thus changes from linear to elliptical and to circular (when the E vector is at a 45 degree angle 'with the plates) to elliptical and then to linear each one quarter revolution of the craft. The probes are orthogonal with each other so as to provide an impedance match therebetween. The 45 degree orientation of the probes with the plates and the time varying polarization (linear each quarter revolution and alternately circularly polarized each one-quarter revolution) provides equal coupling of power to each probe whether the wave is linear, circular or elliptically polarized. Accordingly, the antenna and waveguide coupling apparatus shown in FIGURES 1 and 2 insure the desired operability of receivers provided for redundancy purposes. Should one of the receivers cease operating, this arrangement of our invention assures continued application of signals to the remaining receiver.

FIGURE 3 illustrates an embodiment of our invention for combining and applying all of the received power to one only of two receivers, but wherein failure of the combining means automatically results in the received energy being divided equally between the two receivers. In the arrangement of FIGURE 3, a waveguide 14 is provided at one end with slots 16, such slotted portion being located between biconical reflectors 18', 20', all as in the manner shown in FIGURE 1. Similarly, the waveguide 14 is provided with corresponding quarter-wave plates 22, 24, output probes 26', 28, and connectors 30', 32' to the receivers 34, 36.

However, the arrangement of FIGURE 3 differs from that of FIGURE 1 in that intermediate the slotted end of the waveguide and the quarter-wave plates 22, 24, is a polarization converter which facilitates coupling the total incident power to only one of the output probes, i.e., to

one of the receivers. Such converter as illustrated includes a ferrite element, which may be a rod or, as shown, a sleeve 40, located within the waveguide intermediate its slotted end and the quarter-wave plates 22, 24'.

Surrounding the waveguide and the sleeve 40 is an energizing coil structure 42. In one form, two-phase windings and pole pieces as are employed in a two-phase induction motor are suitable for the structure 42. With such arrangement, which may have a rotating 4-pole field each responsive to signals at twice the spin frequency, fixed two phase alternating voltages are applied to the coils so that the currents therein cause the magnetic field in the ferrite to be shifted a predetermined amount. Also, the linearly polarized wave coupled to the waveguide is converted to a circularly polarized wave by the operation of the ferrite element and the energized coil structure.

The output probes 26, 28' in this case are positioned on one side of the quarter-wave plates 22', 24', so that they are displaced 45 from the quarter-wave plates and 90 from each other. The orthogonal spacing of the output probes 26', 28 matches that of the components of the circularly polarized wave previously mentioned. The sleeve 40 is made with appropriate dimensions and properties, in accordance with well-known design criteria, so that currents of predetermined magnitudes and directions in the coil structure 42 determine whether the wave emerging past the sleeve 40 is a right-hand or left-hand circularly polarized wave. The shift is such that the linearly polarized wave resulting from conversion effected by the quarter-wave plates 22, 24 is one in which the electric vector is aligned with one only of the output probes 26, 28'. For one direction of phase shift, e.g., to righthand circular polarization, the ensuing conversion to linear polarization by the plates 22', 24' results in the electric field being coupled to the output probe 26, and hence to the receiver 34. For such a relative phase shift in the opposite direction, e.g., conversion to left-hand circular polarization, the ensuing conversion to linear polarization by the plates 22, 24 results in the electric field being coupled to the output probe 28' and hence to the receiver 36.

Thus, it will be seen that the arrangement of FIG- URE 3 is one in which twice as much power is applied to a receiver than occurs in the arrangement of FIGURE 1, but with the same antenna structure. Also, the wide band characteristics of the arrangements of FIGURES 1 and 3 are the same.

The antenna arrangement of FIGURE 3 also has the advantage that, in the absence of current through the coil structure 42, e.g., loss of excitation power in the coil, the system is still operative. In the event of such failure, the antenna and waveguide coupling becomes the same as that of FIGURE 1, i.e., the received linearly polarized energy is phase shifted equally in the sleeve 40 and appears past the plates 22, 24' with a polarization-wircular, elliptical or linear-depending upon the azimuthal angle of incidence of the received energy. Regardless of the type of polarization or the angle of incidence, the energy is applied equally to the receivers 34, 36.

Referring to FIGURE 4, there is shown the antenna and waveguide coupling arrangement of FIGURE 1, wherein the connectors 30, 32 of the output probes 26, 28 are connected to respective R-F amplifiers 50, 51. The outputs of the amplifiers 50, 51 are connected to the connectors 52, 53 of orthogonal input probes 54, 55 at one end of a cylindrical waveguide 56. Additionally, a small portion of the outputs of the amplifiers 50, 51 are applied to respective mixers 60, 61, to which a single local oscillator 62 is also connected. The oscillator and mixers are employed to develop outputs from the mixers which are at a considerably lower intermediate frequency, e.g., where the received energy, and corresponding outputs of the amplifiers 50, 51 are of a relatively high frequency of the order of 6,000 mHz., the frequency of the local oscillator 62 may, for example, be of the order of 5,930 mHz., thereby causing the outputs of the mixers 60, 61 to be intermediate frequency signals of the order of 70 mHz.

The outputs of the mixers 60, 61 are applied to respective I.F. amplifier and limiter networks 63, 64, the outputs of which in turn are connected to a phase detector 65. The output of the phase detector 65 is a signal voltage which represents the aspect angle (or angle of incidence) of the incident signals in terms of the coordinate system of the body 12.

As previously mentioned, the signals from the amplifiers 50, 51 are also applied to connectors 52, 53 of orthogonal input probes 54, 55 at one end of a waveguide 56. The waveguide 56 includes a pair of diametrically opposed quarter-wave plates 68, 69 interposed between a ferrite element 40 and the input probes 54, 55. As shown, a coil structure 42 surrounds the sleeve 40 and the waveguide 56. The signals thus applied to the input probes 54, 55 set up a polarized wave, which appears past the quarter-wave plates 68, 69 as a linearly polarized wave. In the manner previously explained in connection with the corresponding parts in FIGURE 3, the ferrite element 40' and the coil structure 42' cooperate to convert the linearly polarized wave to either a right-hand or left-hand circularly polarized wave.

Following the ferrite element 40, the waveguide 56 includes a second pair of diametrically opposed quarter- Wave plates 71, 72, which convert the circularly polarized wave to a linearly polarized wave. Accordingly, depending upon the direction of phase shift effected by currents in the coil structure 42, all of the energy propagated through the waveguide 56 is coupled in phase to one of two orthogonal output probes 73, 74, having respective connectors 75, 76 connected to the receivers 34, 36.

As in the arrangement of FIGURE 3, failure of polarization converter results in the power being applied equally to the two receivers. In such event, the quarterwave plates 71, 72, as in the case of the quarter-wave plates 22', 24' previously described, cause the energy to be applied equally to the output probes 73, 74.

A still further advantage of the arrangement of FIG- URE 4 is that, while it permits the received signal energy to be applied to one receiver alone, it substantially reduces the amount of noise that can be coupled to either receiver, and hence improves the signal-to-noise ratio of the receiver system. In this connection, the signal voltages applied through the amplifiers 50, 51, to the input probes 54, 55 are coherent, i.e., differ only in phase, and thus add coherently in the receiver associated with the output probe to which the electric field is coupled. However, the noise power in each path is separately random, and thus adds non-coherently in such receivers. Therefore, there is a substantially improved signal-to-noise ratio at the output probe to which the energy is coupled.

As previously mentioned, the sense of the phase shift of the circularly polarized wave established by the converter 40, 42' is determined by the currents set up in the coil structure 42'. In this connection, there is shown in FIGURE 4 a current supply source 80 having output leads 81, 82, and a switch 84 is connected between the source 80 and the coil structure 42'. The position of the switch determines current flow through the coil structure, and hence the direction of phase shift. Accordingly, one position of the switch causes the combined signal power to be coupled to one output probe 73, and hence to the receiver 34. The other position of the switch causes the total power to be coupled to the other output probe 74, and hence to the receiver 36.

Let it be assumed that the switch 84 is initially in the position for effecting a right-hand circularly polarized wave out of the ferrite element 40'. Also, assume that such operation causes the combined signal power to be coupled to the output probe 73, and hence to the receiver 34.

Now let it be assumed that the receiver 34 stops functioning. For continued utilization of received signals, this circumstance necessarily requires that the incident signal power be applied to the remaining receiver 36. It is therefore necessary to operate the switch 84 to cause a change in current flow and to energize the coil structure 42' to effect a left-hand circular polarization of the wave leaving the ferrite element 40', whereby, following conversion to linear polarization by the plates 71, 72, the electric field is coupled to the output probe 74 for the receiver 36.

While changing the sense of phase shift has been referenced to a failure of the receiver 34, it should be recognized that other considerations might dictate that the signal energy be switched to the other receiver. For eX- ample, the receiver 34 may be operative but it may be desired to have both receivers operate on a time-sharing basis. In such case, a timing source (not shown) may be provided for periodically operating the switch 84 to couple the power alternately to the receivers.

FIGURE 4 also illustrates an example wherein the antenna structure of FIGURE 3 is used for transmitting signals. The orthogonal probes 26', 28- are input probes, to the connectors 30', 32' of which the outputs of respective power amplifiers 91, 92 are connected.

Signals to the power amplifiers are derived from the receivers 34, 36. The receiver outputs are connected to mixers 93, 94, to which a local oscillator 95 is also connected. The mixers are connected to a hybrid 98 which has output connections to the power amplifiers.

As shown, the coil structure 42 is connected to a current supply source 99 through a switch 100. The source 99 is one capable of developing currents i i in respective output leads 101, 102 that vary as follows:

i -cos 2w t i -sin 2w t The switch 100 may be a manually or electrically controlled double-pole, double-throw switch. In one position, the switch 100 connects the leads 101, 102 to the coil structure 42, and in its other position it reverses the connections. In each position, the varying current flow causes the transmission of a rotating linearly polarized wave. However, the radiation pattern is rotated in opposite directions for the two switch positions.

In this latter connection, the hybrid 98 may be a conventional device for providing outputs corresponding to the sum and difference of signals applied thereto. Inasmuch as normal operation of the system of FIGURE 4 results in only one receiver being energized, the magnitudes of the outputs of the hybrid are the same. The signals applied to the probes 26', 28' are coupled into the waveguide 14' as a linearly polarized wave. After conversion to circular polarization by the quarter-wave plates 22', 24', the energized coil structure 42 and the ferrite element 40 effect conversion to a spinning linearly polarized wave. For one relation of currents, the wave is rotated in one direction. For the other relation of currents, the wave rotates in the opposite direction.

Instead of a rotating beam, the transmitted signal may be radiated in one direction only. For this purpose, the current source 99 is replaced with one like the source 80. Or branch leads (not shown) may be connected between the leads 81, 82 and the switch 100, thereby to permit the same fixed currents to be applied to both coil structures 42, 42'.

The output of the phase detector 65 may be utilized to establish transmission in the direction from which the received signals arrived. To effect such control, the phase detector 65 may be coupled to the current supply source (not shown) that is connected to the switch 100, to establish currents of direction and magnitude corresponding to the output of the phase detector, such as to effect a phase shift by the converter 40, 42 as to orient the transmitted beam in the direction of the received signals.

Additionally, it will be recognized that this invention embraces a variety of arrangements for coupling signals to the input probes of the transmitter antenna. Either receiver could be coupled to either or both power amplifiers. The power amplifiers may be fed from a separate signal source, e.g., transducers operable in response either to the output of a receiver or to separate commands from a remote source.

A still further transmitter arrangement is shown in FIGURE 5, wherein the antenna structure of FIGURE 1 is employed. As shown, power amplifiers 104, are coupled to the connectors 30, 32. Control of the application of power from the power amplifiers 104, 105 to the probes 26, 28 is effected through phase shifters 106, 107 and control means 108 therefor. In this connection, if desired, the phase of the power applied to the probes may be shifted so as to cause a beam to be radiated in a predetermined direction. Any suitable phase shifter control means may be employed for this purpose.

In a still further modification of this invention, a receive-transmit system employs identical antenna structures as in FIGURE 1 for receiving and transmitting antennas. Referring to FIGURE 6, the antenna structure 10, waveguide 14 and receivers 34, 36 are coupled for respective mixers 110i, 111, both of which are coupled to a common local oscillator 112. The mixers are coupled to power amplifiers 113, 114, the outputs of which are connected to the connectors 30', 32' of the input probes 26, 28' of an identical waveguide 14 and antenna structure 10.

By appropriate initial angular positioning of the two antenna structures in FIGURES 46 with respect to one another, the signals are transmitted in the direction from which the received signals arrived. Thus, this system in operation is a retrodirective system.

Antennas as described herein may be made quite small. For example, a bicone antenna having a 30 bandwidth, for transmitting or receiving signals of, say, 6,000 mHz., employs biconical elements of approximately 6-in. diameter, with a S-in. vertical spacing at their perimeters, and with a waveguide of the order of l-in. diameter. The waveguide may be less than a foot long, but may be made longer as desired.

From the foregoing, it will be apparent that various modifications may be made in the various structures and networks shown and described without departing from the spirit and scope of this invention, as embraced by the appended claims.

We claim:

1. In combination: an antenna structure adapted to receive linearly polarized signals;

signal handling means for accepting the received signals as a linearly polarized wave;

a waveguide coupling said antenna structure and said signal handling means for propagating polarized waves;

polarization converter means for changing the polarization of signal waves entering said waveguide and propagating between said antenna structure and signal handling means;

output energy coupling means associated with said waveguide and coupled to said polarized waves;

receiving means for the signal handling means being coupled to said output energy coupling means;

and conversion means intermediate said antenna structure and said polarization converter means for converting the linearly polarized Wave to a circularly polarized Wave of predetermined sense said polarization converter means converting said circularly polarized wave to a linearly polarized wave so that all of the electric field is coupled to said output energy coupling means.

2. In combination: an antenna structure adapted to receive linearly polarized signals from a plurality of directions;

signal handling means for accepting the received signals as a linearly polarized wave;

a waveguide coupling said antenna structure and said signal handling means for propagating polarized waves;

polarization converter means for changing the polarization of signal waves entering said waveguide and propagating in one direction between said antenna structure and signal handling means;

first and second output energy coupling means associated with said waveguide to have portions of the electric field coupled thereto;

first and second receivers for the signal handling means being respectively coupled to said first and second output energy coupling means;

and conversion means ahead of said converter means for converting the linearly polarized Wave to a circularly polarized wave, said converter means converting the circularly polarized wave to a linearly polarized wave, and said first and second output energy coupling means being positioned so that the total electric field of the linearly polarized wave can be coupled to one of them.

3. The combination of claim 2, further including means for operating said conversion means to cause the total electric field to be switched from one of said first and second output energy coupling means to the other.

4. The combination of claim 3, wherein the antenna structure includes a portion of said waveguide, said portion having a plurality of spaced slots.

5. The combination of claim 4, wherein said first and second output energy coupling means are orthogonal.

6. In combination: an antenna structure adaptedto receive linearly polarized signals from a plurality of directions;

signal handling means for accepting the received signals as a linearly polarized wave;

a waveguide coupling said antenna structure and said signal handling 'means for propagating polarized waves;

polarization converter means for changing the polarization of signal waves entering said waveguide and propagating 'between said antenna structure and signal handling means;

first and second output energy coupling means associated with said waveguide to have portions of the electric field coupled thereto;

and means included in said signal handling means and coupled to said first and second output energy coupling means for developing a signal representing the direction from which the received signal energy arrived at the antenna structure.

7. The combination of claim 6 wherein said direction signal determining means includes respective amplifiers coupled to said output energy coupling means; and means coupled to said amplifiers for developing a signal representing the phase difference between the signals from said amplifiers.

8. In combination: an antenna structure adapted to receive linearly polarized signals;

a first waveguide coupled to said antenna structure for propagating polarized waves; first polarization converter means for changing th polarization of signal waves entering said first waveguide and propagating between said antenna structure and signal handling means;

first and second output energy coupling means associated with said first waveguide to have portions of the electric field coupled thereto;

a second waveguide having orthogonal input energy coupling means for causing signals from said output energy coupling means of said first waveguide to b coupled into said second Waveguide;

a pair of orthogonal output energy coupling means associated with said second waveguide at a location spaced from said input energy coupling means;

second polarization converter means intermediate said orthogonal input and output energy coupling means of said second waveguide for developing a linearly polarized wave;

conversion means intermediate said second converter mean and orthogonal output energy coupling means of said second waveguide to convert the linearly polarized wave to a circularly polarized wave;

and third converter means intermediate said conversion means and said orthogonal output energy coupling means of said second waveguide for converting the circularly polarized wave to a stationary linearly polarized wave to be coupled to one of said orthogonal output energy coupling means.

9. The combination of claim 8, wherein said conversion means includes a ferrite element within the waveguide and a coil structure surrounding said waveguide intermidate the ends of said ferrite element, said coil structure being adapted to have currents applied thereto to cause the circularly polarized wave estabished thereby to have a predetermined sense of circular polarization.

10. The combination of claim 9 including a source of currents to be applied to said coil structure;

a switch connected between said current source and coil structure;

said switch having one state in which the currents applied to said coil structure from said current source etfect one sense of polarization of the circularly polarized wave, such one sense of polarization causing the electric field associated with the stationary linearly polarized Wave to be coupled to one of said orthogonal output energy coupling means;

said switch having another state in which currents applied to said coil structure from said current source eifect the opposite sense of polarization of the circularly polarized wave, such opposite sense of polarization causing the electric field associated with the stationary linearly polarized wave to be coupled to the other orthogonal output energy coupling means.

11. In combination:

a waveguide;

first and second energy coupling means associated with said waveguide for coupling signal energy thereto;

means responsive to the signal energy to establish a spinning linearly polarized wave to produce a rotating electric field;

and an antenna coupled to the waveguide for radiating a rotating beam in response to the rotating electric field.

12. The combination of claim 11, wherein said spinning means includes a ferrite element within said waveguide;

a two-phase coil structure surrounding said ferrite element;

and means for applying currents to said coil structure to cause the signal energy to be converted to a linearly polarized wave.-

13. In combination:

a cylindrical waveguide;

means to insert signal energy into said waveguide as a polarized wave to be propagated along the waveguide;

output energy coupling means associated with said waveguide for receiving substantially all of said signal energy;

and means operable upon the Wave to selectively establish and couple said energy to said output energy coupling means in the form of a stationary linearly 'polarized wave.

14. The combination of claim 13, wherein the means for selectively establishing the linearly polarized wave includes:

first converter means for converting the time varying polarized wave into the rotating linearly polarized wave;

a ferrite element intermediate said first converter means and said output energy coupling means;

magnetic field control means associated with said ferrite element to impart a rotation synchronous with the linear electric field and convert the linearly polarized wave into a circularly polarized wave;

and second converter means between said ferrite element and said output energy coupling means to convert the circularly polarized wave to a linearly polarized wave at said output energy coupling means.

15. In combination: an antenna structure adapted to transmit signals in a plurality of directions;

signal handling means including a pair of energy coupling means;

a waveguide coupling said antenna structure and said pair of energy coupling means for propagating polarized waves therebetween;

polarization converter means for changing the polarization of signal Waves entering said waveguide and propagated in one direction between said antenna structure and said signal handling means;

respective power amplifier means coupled to said energy coupling means to introduce energy into the waveguide for transfer by said antenna structure;

respective controllable phase shifters coupled to said power amplifier means, said phase shifters being adapted to have signals applied thereto;

and control means coupled to said phase shifters to cause signals to be applied to said energy coupling means in a predetermined phase relation.

16. In combination: a first antenna structure adapted to receive linearly polarized signals from a plurality of directions;

signal handling means for accepting the received signals as a linearly polarized wave;

a first waveguide coupling said antenna structure and said signal handling means for propagating polarized waves;

polarization converter means for changing the polarization of signal waves entering said first waveguide and propagating between said antenna structure and signal handling means;

first and second output energy coupling means associated with said first waveguide to have a portion of the electric field coupled thereto;

first and second receivers for the signal handling means being respectively coupled to said first and second output energy coupling means;

a second antenna structure;

a second waveguide coupled at one end to said second antenna structure;

a pair of spaced energy coupling means associated with said second waveguide adjacent its other end;

respective mixers coupled to said first and second receivers;

a common local oscillator coupled to both mixers;

and a respective power amplifier connected between each mixer and one of the spaced energy coupling means.

References Cited UNITED STATES PATENTS 2,412,320 12/1946 Carter.

2,771,605 11/1956 Kirkman 343-100 X 2,857,575 10/1958 Zaleski. 3,281,843 10/1966 Plummer.

OTHER REFERENCES Final Report on the Relay I Program, Chapter 5, The Microwave Repeater, pages -100, NASA Scientific and Technical Aerospace Reports, NASA SP-76, 1965.

RICHARD A. FARLEY, Primary Examiner.

T. H. TUBBESING, Assistant Examiner.

US. Cl. X.R. 

